Motion and orientation sensor

Abstract

A motion and orientation sensor and measuring device has an electric circuit contact actuated by a body of conductive fluid on disturbance of the conductive fluid by gravity, vibration or otherwise. A ball and socket joint adjustably mounts a disk-shaped container for the fluid through attachment of the ball to a support which may be structure of the object guarded by the sensor. A releasable internal-expansion locking mechanism in the ball and actuable from above laterally contacts the socket and fixes the angular relation of ball-to-socket as desired, and numerical measurement features are provided.

What is claimed and desired to be secured by United States Letters Patent is: 
     
       1. A device for detecting changes in inclination of an object comprising: a closed container having an interior which is at least partly defined by side walls which are electrically non-conductive and diametrically separated by a distance 2R, said container interior having a height H and a top wall and being at least partially filled with electrically conductive fluid having a top surface which subsists in a substantially uninterrupted plane between said side walls and which is spaced a distance h from said top wall when said height H is vertically oriented, wherein the ratio 2R/H is much greater than one;   mounting means suspending said container in fixed orientation in relation to said object;   electrical circuit means responsive to a predetermined degree of disturbance of said fluid in said container for providing an electrical signal representing an inclination change in said object, said electrical circuit means including an electrical switch comprising: a first electrode positioned in said container to be continuously immersed in said conductive fluid when said height H is vertically oriented and over a predetermined range of inclinations of said height H;   a second electrode positioned in said container above said top surface of fluid a distance h' no greater than h when said height H is vertical but immersed in said fluid when inclination change in said height H causes said predetermined degree of disturbance of said fluid.     
     
     
       2. The device according to claim 1 wherein said mounting means comprises a curved member and a socket member, said socket member having an interior surface contoured to match at least part of said curved member and positioned to frictionally engage said curved member. 
     
     
       3. The device according to claim 2 wherein said curved member is a ball fixedly secured with respect to said object and wherein said socket member is fixedly secured with respect to said container. 
     
     
       4. The device according to claim 2 further comprising friction means for providing frictional opposition to relative movement between said curved member and said socket member. 
     
     
       5. The device according to claim 1 wherein said container is a cylinder having its longitudinal axis aligned with the vertical when said height H is vertical. 
     
     
       6. The device according to claim 1 wherein said second electrode terminates in an annular electric contact of outer radius R'. 
     
     
       7. The device according to claim 1 further comprising means for altering switch sensitivity and actuation setting comprising means for varying an inside dimension of the container. 
     
     
       8. The device according to claim 5 wherein said mounting means includes a ball fixed to the object, a corresponding socket for the ball for movably mounting the conductive fluid container below the ball, and means associated with the ball and socket for fixing said container with respect to the ball. 
     
     
       9. The device according to claim 8 further comprising means for automatically aligning the axis of said cylinder with the vertical such that the net restoring torque acting on the suspended container-socket body when unconstrained remains greater than zero for intolerable deflections of said axis from the vertical. 
     
     
       10. The device according to claim 8 further comprising means for constraining rotation of the socket relative to the ball comprising expandable members in the ball. 
     
     
       11. The device according to claim 10 wherein the expandable members communicate with a bore in the ball and further including means protruding above the ball for causing said expandable members to expand upon actuation vertically. 
     
     
       12. The device according to claim 11 further comprising means for actuating the protruding means vertically. 
     
     
       13. The device according to claim 12 wherein the expandable members expand to laterally bear on the socket. 
     
     
       14. The device according to claim 13 wherein said means for actuating includes a further member having a vertically elongate taper, said further member having a portion slidably fitting said bore, a part of the bore being dimensioned for clearing the taper. 
     
     
       15. The device according to claim 14 wherein the ball includes a transverse passage passing through the ball to at least one portion of the ball exterior and communicating with the bore, said expandable means comprising at least one brake rod slidably contained within the transverse passage, the brake rod having sufficient length to extend outward and press on the socket when urged by the taper of said member upon said actuation. 
     
     
       16. The device according to claim 15 wherein the transverse passage passes through the ball exterior at diametrically opposed locations, and wherein a second brake rod is provided in the transverse passage and is of sufficient length to extend out and press on the socket when urged by the taper for equalizing pressure on and stabilizing the socket. 
     
     
       17. The device according to claim 1 wherein said container is a hollow cylindrical disc having an inside radius R and inside height H. 
     
     
       18. The device according to claim 17 wherein the conductive fluid and the inside of the container top are of opposite polarity. 
     
     
       19. The device according to claim 7 further including means for adjusting void depth h in the container including adjustable means for raising the conductive fluid into a portion of the container void, said adjustable means including a lower portion of the container in adjustable threaded engagement within an upper portion of the container. 
     
     
       20. The device according to claim 18 further including means for altering sensitivity and actuation setting comprising means for varying h, R and H, wherein a change in orientation of said container axis by at least angle A with respect to the vertical actuates the device, where, based on actual geometry and assuming the conductive fluid surface is a plane and fluid volume is constant,   tan A=h/R, for H≧2h; and       D.sub.4 =3d.sub.4 R.sup.2 tan.sup.2 A arc cos (-d.sub.4 /R tan A)=0, for h 21 H≦2h,       when d.sub.4 ≧0H/2R≦tan A≦H/R, πh/(π-2/3)≦H≦2h,       when d.sub.4 ≦0, H/R≦tan A<∞, h<H≦πh/(π-2/3);       where d.sub.4 =H-R tan A and       D.sub.4 =(2R.sup.2 tan.sup.2 A+d.sub.4.sup.2)(R.sup.2 tan.sup.2 A-d.sub.4.sup.2).sup.1/2 -3πR.sup.2 (H-h) tan.sup.2 A;     based on a lamina of conductive fluid surrounding the container axis and assuming the fluid surface is a line and the fluid area is constant, the approximate actuation angle A is     tan A=tan A, for H≧2h; and       tan A=H.sup.2 /4R(H-h), for h<H≦2h.     
     
     
       21. The device according to claim 6, with said annular contact positioned symmetrically about the axis of a cylindrical container, further including means for altering switch sensitivity and actuation setting comprising means for varying h, h', R, R' and H, wherein a change in orientation of said container axis by at least angle A with respect to the vertical actuates the device since   tan A=h'/R', 0≦tan A≦(H-h)/R, h<H≦2h;       D.sub.1 +3d.sub.1 R.sup.2 tan.sup.2 A arc cos(-d.sub.1 /R tan A)=0,       when d.sub.1 ≧0, (H-h)R≦tan A≦tan A.sub.1, πh/(π-2/3)≦H≦2h,       when d.sub.1 ≦0, (H-h)/R≦tan A≦tan A.sub.2, h<H≦πh/(π-2/3);       D.sub.2 +3d.sub.1 R.sup.2 [arc sin (d.sub.1 /R tan A)+arc sin (d.sub.2 /R tan A)] tan.sup.2 A=0,       when d.sub.1 ≧0, tan A.sub.1 ≦tan A<∞, πh/(π-2/3)≦H≦2h,       when d.sub.1 ≦0, tan A.sub.2 ≦tan A<∞, h<h≦πh/(π-2/3);       D.sub.3 +3d.sub.3 R.sup.2 tan.sup.2 A.sub.i arc cos (-d.sub.3 /R tan A.sub.i)=0,       when i=1, d.sub.3 ≧0, H/2R≦tan a.sub.1 H/R, πh/(π-2/3)≦H≦2h,       when i=2, d.sub.3 ≦0, H/R≦tan A.sub.2 <∞, h<H≦πh/(π-2/3);       HR.sup.2 arc cos (R'/R)-HR'(R.sup.2 R'.sub.2).sup.1/2 -πR.sup.2 (H-h)=0,       tan A=∞, h<H≦2h;       tan A=h'/R',       when 0≦tan A≦h/R, H≧3πh/2,       when 0≦tan A≦H/2R, 2h≦H≦3πh/2;       D.sub.2 +3d.sub.1 R.sup.2 [arc sin (d.sub.1 /R tan A)+arc sin (d.sub.2 /R tan A)] tan.sup.2 A=0,       d.sub.1 >0, H/2R≦tan A<∞, 2h≦H≦3πh/2;     and     2(R.sup.2 tan.sup.2 A-d.sub.2.sup.2).sup.3/2 +3d.sub.2.sup.2 (R.sup.2 tan.sup.2 A-d.sub.2.sup.2).sup.1/2       +3d.sub.2 R.sup.2 tan.sup.2 A arc cos (-d.sub.2 /R tan A)-3πR.sup.2 h tan.sup.2 A=0,       h/R≦tan A≦H/R, H≦3πh/2;     where as appropriate     d.sub.1 =H-h+h'-R' tan A,       d.sub.2 =h-h'+R' tan A, d.sub.3 =H-R tan A.sub.i,       D.sub.1 =(2R.sup.2 tan.sup.2 A+d.sub.1.sup.2)(R.sup.2 tan.sup.2 A-d.sub.1.sup.2).sup.1/2 -3πR.sup.2 (H-h) tan.sup.2 A,       D.sub.2 =(2R.sup.2 tan.sup.2 A+d.sub.1.sup.2)(R.sup.2 tan.sup.2 A-d.sub.1.sup.2).sup.1/2 -2(R.sup.2 tan.sup.2 A-d.sub.1.sup.2).sup.3/2 -d.sub.2.sup.2 (R.sup.2 tan.sup.2 A-d.sub.2.sup.2).sup.1/2 +3HR.sup.2 tan.sup.2 A arc cos (d.sub.2 /R tan A)-3πR.sup.2 (H-h) tan.sup.2 A, and       D.sub.3 =(2R.sup.2 tan.sup.2 A.sub.i +d.sub.3.sup.2)(R.sup.2 tan.sup.2 A.sub.i -d.sub.3.sup.2).sup.1/2 -3πR.sup.2 (H-h) tan.sup.2 A.sub.i     wherein the above relationships for the actuation angle A are based on actual geometry assuming the conductive fluid surface is a plane and the fluid volume is constant; and wherein, based on a lamina of conductive fluid containing the container axis and assuming the fluid surface is a line and the fluid area a constant on the lamina, the approximate actuation angle A is ##EQU1##     where R(-1+2h/H)≦R'≦R, h<H≦2h, 0≦h'≦h, B.sub.1 =(H-h+h').sup.2,       B.sub.2 =2(R-R')(H-h+h')-4R(H-h), B.sub.3 =(R-R').sup.2 ; and ##EQU2##       where 0<R'≦R, H≧2h, 0≦h'≦h,       B.sub.4 =(Rh).sup.1/2 (Rh'-R'h=R'h').sup.1/2.     
     
     
       22. The device according to claim 1 wherein said container includes a conductive top wall having an interior surface exposed to the container interior, which conductive top wall serves as said second electrode.